An LCD has the advantages of portability, low power consumption, and low radiation, and has been widely used in various portable information products such as notebooks, personal digital assistants (PDAs), video cameras and the like. Furthermore, the LCD is considered by many to have the potential to completely replace CRT (cathode ray tube) monitors and televisions.
FIG. 3 is a schematic diagram of a typical LCD. The LCD 10 includes an LCD panel 11, a backlight 12 for projecting light to the LCD panel 11, and an LCD driving circuit 13. The LCD panel 11 includes a display area 114 for displaying images, and a periphery circuit area 116. The LCD driving circuit 13 includes a backlight driving circuit 17, a panel driving circuit 18 positioned on the periphery circuit area 116, a power supply device 16, and a system control device 15.
The power supply device 16 provides a voltage to drive the backlight driving circuit 17 and the panel driving circuit 18. The system control device 15 provides a backlight driving signal to the backlight driving circuit 17, and a control signal and a data signal to the panel driving circuit 18. The panel driving circuit 18 drives the LCD panel 11 to display images on the display area 114 according to the control signal and the data signal. The backlight driving circuit 17 drives the backlight 12 according to the backlight driving signal.
FIG. 4 is a block diagram of the panel driving circuit 18. The panel driving circuit 18 includes a gate driver 184, a source driver 183, a latch circuit 182, a gamma adjustment and grayscale voltage generation circuit 187, a regulator circuit 186, a first booster circuit 185, and a panel interface circuit 181. The panel driving circuit 18 is an integrated circuit.
The first booster circuit 185 receives the voltage from the power supply device 16 and drives the gate driver 184 and the regulator circuit 186. The regulator circuit 186 supplies driving voltages to the gate driver 184, the source driver 183, the latch circuit 182, and the gamma adjustment and grayscale voltage generation circuit 187. The panel interface circuit 181 receives the control signal and the data signal from the system control device 15, and provides them to the gate driver 184, the first booster circuit 185, the regulator circuit 186, the latch circuit 182, and the gamma adjustment and grayscale voltage generation circuit 187. The latch circuit 182 and the gamma adjustment and grayscale voltage generation circuit 187 are used to drive the source driver 183 according to the control signal and the data signal. The gate driver 184 is used to scan the LCD panel 11 according to the control signal and the data signal. The source driver 183 provides a plurality of grayscale voltages to the LCD panel 11 when the display area 114 is scanned by the gate driver 184.
FIG. 5 is a block diagram of the backlight driving circuit 17. The backlight driving circuit 17 includes a backlight interface circuit 171, a second booster circuit 172, and an analog/digital transform circuit 173.
The second booster circuit 172 receives the voltage from the power supply device 16 and drives the analog/digital transform circuit 173. The backlight interface circuit 171 receives the backlight driving signal from the system control device 15, and provides it to the second booster circuit 172 and the analog/digital transform circuit 173. The analog/digital transform circuit 173 is used to drive the backlight 12 according to the backlight driving signal. The backlight driving circuit 17 is an integrated circuit.
Because both the backlight driving circuit 17 and the panel driving circuit 18 include a booster circuit 172, 185 therein, the layout of conductive lines 161 that are used to supply the electrical power to the backlight driving circuit 17 and the panel driving circuit 18 from the power supply device 16 has a complicated configuration. Furthermore, because both the backlight driving circuit 17 and the panel driving circuit 18 include an interface circuit 171, 181 therein, the lay out of conductive lines 151 that are used to transmit signals also has a complicated configuration too.
It is desired to provide a driving circuit of an LCD which overcomes the above-described deficiencies.